Pressure that can melt diamond, an electromagnetic pulse that can kill, and enough current to light 100 million light bulbs. Such are the extremes within the Z machine at Sandia National Laboratories in Albuquerque, New Mexico. In this image, artificial lightning spread like a wave through Z's 33-metre-wide interior.

Designed to research nuclear fusion, Z can also help explore the behaviour of materials at ultra-high pressures and temperatures, and act as a source of intense X-rays. These abilities spring from the machine's massive pulses of current.

First the current is fired at hundreds of tiny tungsten wires, vaporising them to form a cloud of charged particles, or plasma. The plasma produces a magnetic field that forces the particles to line up at the centre of the machine, so that they point out of the horizontal plane of its surface, along the vertical or z-axis - hence the machine's name. This arrangement causes the particles to collide, producing exceptionally powerful X-rays.

Z's magnetic field can also be harnessed to accelerate metal plates and squish materials. In fact, Sandia researcher Marcus Knudson was able to apply over 5 million times atmospheric pressure to squeeze diamond, turning the precious stone into a puddle.

The magnetic field is invisible, of course. Shown here is lightning that sparks out of metal protrusions inside Z when the current is switched on. Blink and you'll miss it: this image was taken within a split second of the machine's firing.

If you are thinking about visiting Sandia to see the light show in person, you are out of luck. The top of the machine is now almost completely covered with instruments.

In any case, Z is dangerous. "There is a huge electromagnetic pulse produced that would likely kill anyone that was trying to observe a firing of the accelerator," says Knudson. "So I have only seen this in pictures."